On the afternoon of July 3rd Confederate general Robert E. Lee ordered Pickett's division (amongst others) to attack the Union position on Cemetery hill in an all out effort to break the Union line. After an hour (or more) long cannonade, which achieved little damage as the Confederate artillery mostly overshot, Pickett, reluctantly, sounded the attack and forward went some 12.500 men in what would be later called Pickett's Charge.
Pickett's three brigades came in from the left half of this view, to the left of Codori's farm (the red building) marching obliquely to the wall. Pettigrew's six bloodied brigades came on from the center and right in a straight line. After crossing the wooden fence bordering Emmitsburg road) musket-volley's intermingled with cannon fire and wrecked the attacking formation.
The Copse of trees where the Pickett-Pettigrew charge hit home on the afternoon of July 3rd is on the right of this picture taken at 'the Angle'. This location and moment in history is called the 'High Water Mark' of the Confederacy. It was here Armistead broke through for a moment, raised his hat on his sword and shouted his men on only to be mortally wounded moments later when the Union troops reformed and counter-attacked.
On the right side of the picture we can see the wall making a sharp angle to the right and a few dozen meters to the rear -in front of the markers- the continuatie of the stone wall. It was here Pettigrew's (formerly commanded by Heth) battered division assailed and crossed the wall. And in fact got further then Armistead at the 'High Water Mark'.
Eventually all Confederate troops where beaten back and streamed across the field towards Seminairy ridge. Lee whept and could only mutter "It is all my fault".
Panorama picture taken from The Gettysburg Daily, a great site for information on Gettysburg amongst which dozens of panorama pictures.